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Rod-coil type miktoarm star copolymers consisting of polyfluorene and polylactide: precise synthesis and structure-morphology relationship

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POLYMER CHEMISTRY 2015年第39期6卷 6959-6972页

作者： Saito, Kengo Isono, Takuya Sun, Han-Sheng Kakuchi, Toyoji Chen, Wen-Chang Satoh, Toshifumi Hokkaido Univ Grad Sch Chem Sci & Engn Sapporo Hokkaido 0608628 Japan Hokkaido Univ Div Appl Chem Fac Engn Sapporo Hokkaido 0608628 Japan Natl Taiwan Univ Dept Chem Engn Taipei 10617 Taiwan

A series of rod-coil miktoarm star copolymers consisting of poly[2,7-(9,9-dihexylfluorene)] (PF) and polylactide (PLA) arms as the rod and coil segments, respectively, were synthesized by combining the chain-growth Suzuki-Miyaura coupling polymerization and living ring-opening polymerization (ROP). First, PFs having a hydroxyl group at the alpha-chain end (PF-BnOH) were prepared by the polymerization of 2-(7-bromo-9,9-dihexyl-9H-fluorene-2-yl) 4,4,5,5-tetramethyl-1,2,3-dioxaborolane using the initiating system of 4-(tetrahydropyran-2'-yloxymethyl)-iodobenzene/Pd-2(dba)(3)/t-Bu3P. After a couple of chain end modifications, PFs having one, two, and three hydroxyl groups at the alpha-chain end (PF-OH, PF-(OH)(2), and PF-(OH)(3), respectively) were obtained with dispersity (D) values of less than 1.29. The obtained PF-OH, PF-(OH)(2), and PF-(OH)(3) were used as the initiators for the organic base-catalyzed ROP of rac-lactide to produce the AB type linear diblock (PF-b-PLA) and AB(2) and AB(3) type miktoarm star copolymers (PF-b-(PLA)(2) and PF-b-(PLA)(3), respectively). The self-assembled nanostructures in the thermally-annealed PF-b-(PLA)(x)s (x = 1, 2, and 3) were evaluated in the bulk by synchrotron small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The PF-b-PLA, PF-b-(PLA)(2), and PF-b-(PLA)(3) with the PF weight fractions of 0.52-0.56 were found to form poorly ordered PLA cylindrical structures in the PF matrix due to a strong rod-rod interaction of the PF segment. On the other hand, these BCPs with the PF weight fractions of 0.22-0.23 exhibited the hexagonally close-packed cylinder (Hex) morphologies, in which the cylindrical PF phase was embedded in the PLA matrix. More interestingly, the domain-spacing (d) values for the Hex morphologies decreased with the increasing PLA arm number despite each BCP having a comparable molecular weight and PF weight fraction: d = 26.4 nm for PF-b-PLA, d = 21.7 nm for PF-b-(PLA)(2), and d = 18.6 nm for

关键词： WEIGHT FRACTION Copolymers Retinopathy of Prematurity programmable logic arrays bioconcentration potential (bcp) COPPER ALLOY NO 955 hex polyfluorenones Initiators Hydroxyl group Molecular weights Polymerization FCGRT gene Polylactides

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Metal influence on the iso- and hetero-selectivity of complexes of bipyrrolidine derived salan ligands for the polymerisation of rac-lactide

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CHEMICAL SCIENCE 2015年第8期6卷 5034-5039页

作者： Jones, Matthew D. Brady, Lauren McKeown, Paul Buchard, Antoine Schaefer, Pascal M. Thomas, Lynne H. Mahon, Mary F. Woodman, Timothy J. Lowe, John P. Univ Bath Dept Chem Bath BA2 7AY Avon England Univ Bath Doctoral Training Ctr Sustainable Chem Technol Bath BA2 7AY Avon England Univ Bath Dept Chem Bath Chem Crystallog Unit Bath BA2 7AY Avon England

In this paper we have prepared a series of Ti(IV), Hf(IV) and Al(III) complexes based on bipyrrolidine salan proligands. The Hf(IV) complexes have all been characterised in the solid-state, the chiral ligands coordinate to Hf(IV) in an alpha-cis manner whereas the meso ligand coordinates in a beta-cis geometry. The Hf(IV) complexes are all active for the ROP of rac-lactide in the melt, with the fluxional meso complex affording a strong isotactic bias P-m = 0.84. As expected Hf(3)(OPr)(2) polymerised L-LA faster than rac-LA (k(app) = 5.9 x 10(-3) min(-1) vs. 3.8 x 10(-3) min(-1)). For Ti(IV) complexes atactic PLA was formed. The salan pro-ligands have also been complexed to Al(III), and the novel Al-Me and Al-OiPr complexes were characterised in the solid and solution state. Al(1)(OPr) was fluxional on the NMR timescale, whereas Al(3)((OPr)-Pr-i) was locked in solution with no exchange. Interestingly, the Al(III) complexes of 3H(2) produce PLA with a very strong heterotactic bias P-r upto 0.87, whereas atactic PLA is produced with 1H(2). For Al(3)(OPr) a linear relationship is observed with M-n and conversion. Experiments with the addition of an equivalent of rac-LA to the selective initiators have also been performed and are discussed.

关键词： Retinopathy of Prematurity programmable logic arrays Coordinates ligands Polymerization ISO

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Toward producing commercial electronics on biodegradable PCB substrates

Toward producing commercial electronics on biodegradable PCB...

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International Spring Seminar on Electronics Technology

作者： Attila Géczy László Gál Bálint Kovács István Hajdu Dept. of Electronics Technology Budapest University of Technology and Economics Budapest

ISBN: (纸本)9781509013906

The paper presents novel research results and progress report towards the production of functional, commercial electronics on biodegradable Printed Circuit Boards (PCB) via presenting the realization of an MP3 player on different eco-friendly substrates. With the production of commercial devices on such base boards, potential e-waste can be reduced. The omission of the traditional epoxy-based FR4 substrates may help in the reduction of harmful materials. Also, with the applied and adapted common PCB fabrication methodology, the prototyping and production steps become cost-effective. The paper details the manufacturing steps and aspects of production. Pilot results of FR4, cellulose-acetate (CA) and novel bioepoxy based circuits are presented, with functional tests. The preliminary results show promising examples of working circuits with proper functionality based on the novel substrates, however different requirements for future improvements are highlighted, to ensure the required reliability and durabilty for commercial use.

关键词： Substrates Digital audio players Standards Soldering Lead programmable logic arrays

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An intelligent model of home support for people with loss of autonomy: A novel approach

An intelligent model of home support for people with loss of...

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International Conference on Control, Decision and Information Technologies (CoDIT)

作者： Kawtar Dahmani Abderrahim Tahiri Olivier Habert Yassine Elmeftouhi SIGL Abdelmalek Essaadi University Tetuan Morocco LCOMS Lorraine University Metz France

During the last decade, efforts have been made to ensure a continuous development within smart home technologies in order to provide comfort, security and conviviality functionalities in home's managing. Among the researches aiming to improve the living conditions and the well-being of residents, the home support for people with loss of autonomy (PLA) living alone is of great importance. Indeed, because of their condition, their independence becomes restricted and their freedom jeopardized, since they are confronted to constantly rely on others for their needs. The idea of conceiving an integrative system came out as a mean to ensure life quality and independence to PLA. Our research project consists of designing and developing a new model of home assistance for PLA, based on smart home technologies such as wireless sensor networks, Data mining, and artificial intelligence. This paper presents an overview of smart home issues in order to introduce our solution of intelligent model support of PLA.

关键词： Wireless sensor networks programmable logic arrays Smart homes Radiofrequency identification Monitoring Computational modeling

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Visible light communication in vehicular ad-hoc networks

Visible light communication in vehicular ad-hoc networks

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IEEE Signal Processing and Communications Applications (SIU)

作者： Seyhan Uçar Sinem Çöleri Ergen Öznur Özkasap Bilgisayar Mühendisliği Bolümü Koç Üniversitesi İstanbul Türkiye Elektrik Elektronik Mühendisliği Bolümü Koç Üniversitesi İstanbul Türkiye

Advances in auto-mobile industry and urbanization enable vehicles communicate with each other and link adjacent cities to form connected smart cities. As a result, vehicular ad-hoc networks (VANETs) have become one of the most relevant communication technologies that aim to reduce traffic congestion, traffic accidents, energy waste and pollution by providing data dissemination about events. However, VANET systems suffer from scarcity of radio frequency (RF) spectrum which pushes researchers to investigate alternative technologies such as visible light communication (VLC). On the other hand, vehicular VLC has drawbacks; sudden glare on drivers at night condition and angular limitation of headlight which are needed to be experimentally evaluated. In this paper, we first present latest concept of vehicular VLC and provide detailed explanation of VLC problems. We then demonstrate experimentally that VLC problems have crucial effect on data packet delivery ratio and received power strength.

关键词： Optical sensors programmable logic arrays

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Nonvolatile online CMOS trimming with magnetic tunnel junctions

Nonvolatile online CMOS trimming with magnetic tunnel juncti...

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IEEE International Symposium on Nanoscale Architectures (NANOARCH)

作者： Sumit Dutta Michael Price Marc A. Baldo Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA

ISBN: (纸本)9781467389273

We design a programmable output delay for digital circuits, making use of the nonvolatile bit storage in magnetic tunnel junctions (MTJs), which are available in hybrid processes with CMOS. We introduce our programmable clock buffers in VLSI dot product and fast Fourier transform (FFT) circuits at the 45 nm node. We reduce the FFT clock skew by 39%. These performance improvements and the ability to reduce timing violations come at less than a 1% increase in area and power.

关键词： Multiplexing Writing programmable logic arrays MOS devices Timing Clocks

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A high efficiency fluorescent lamp electronic ballast design

A high efficiency fluorescent lamp electronic ballast design

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IEEE Congreso Argentino de Ciencias de la Informatica y Desarrollos de Investigacian (CACIDI)

作者： Jhon F. Bayona Harold R. Chamorro Andres C. Sanchez Jacobo Aguillon-Garcia Diego A. Rubio Power Electronics at Universidad Sergio Arboleda Bogota Colombia Universidad de los Andes Bogota Colombia Korea Advanced Institute of Science and Technology Daejeon Korea

This paper presents the design and implementation of an electronic ballast for powering a fluorescent lamp. The purpose of this work is to improve the efficiency of the ballast by implementing a Series Resonant Inverter (SRI) in half-bridge configuration instead classic Series-Parallel Resonant (SPRI); in order to allow to provide the voltage steady state of the lamp. By other hand, this DC-AC converter will supply the voltage lamp ignition. Results on the proposed experimental prototype, using a fluorescent lamp of 32W, shows a better efficiency compared to traditional SPRI configurations.

关键词： Electronic ballasts programmable logic arrays Resistance Resonant inverters Electronic mail Steady-state

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Dynamic Analysis of Cell interactions in Biological Environments under Multiagent Social Learning Framework

Dynamic Analysis of Cell interactions in Biological Environm...

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IEEE International Conference on Bioinformatics and Biomedicine

作者： Chengwei Zhang Xiaohong Li Shuxin Li Jianye Hao School of Computer Science and Technology Tianjin University China School of Computer Software Tianjin University China

ISBN: (纸本)9781509016129

Biological environment is uncertain and its dynamic is similar to the multiagent environment, thus the research results of the multiagent system area are of great significance and can provide valuable insights to the understanding of biology. Learning in a multiagent environment is highly dynamic since the environment is not stationary anymore and each agent's behavior changes adaptively in response to other coexisting learners, and vice versa. The dynamics becomes more unpredictable when we move from fixed-agent interaction environments to multiagent social learning framework. Analytical understanding of the underlying dynamics is important and challenging. In this work, we consider a social learning framework with homogeneous learners (e.g., Policy Hill Climbing (PHC) learners), to model the behavior of players in the social learning framework as a hybrid dynamical system. By analyzing the dynamical system, we obtain some conditions about convergence or non-convergence. It can be used to predict the convergence of the system. At last, we experimentally verify the predictive power of our model using a number of representative games.

关键词： programmable logic arrays Biotic environment Social Learning programmable logic arrays Cell interactions Dynamic analysis Environments DYNAMICAL SYSTEMS Converge Frameworks

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Cyber deterrence in times of cyber anarchy - evaluating the divergences in U.S. and Chinese strategic thinking

Cyber deterrence in times of cyber anarchy - evaluating the ...

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International Conference on Cyber Conflict (CyCon U.S.)

作者： Elsa B. Kania Long Term Strategy Group Washington D.C.

ISBN: (纸本)9781509061723

The advent of the cyber domain has introduced a new dimension into warfare and complicated existing strategic concepts, provoking divergent responses within different national contexts and strategic cultures. Although current theories regarding cyber deterrence remain relatively nascent, a comparison of U.S. and Chinese strategic thinking highlights notable asymmetries between their respective approaches. While U.S. debates on cyber deterrence have primarily focused on the deterrence of cyber threats, Chinese theorists have also emphasized the potential importance of cyber capabilities to enhance strategic deterrence. Whereas the U.S. government has maintained a consistent declaratory policy for response, Beijing has yet to progress toward transparency regarding its cyber strategy or capabilities. However, certain PLA strategists, informed by a conceptualization of deterrence as integrated with warfighting, have advocated for the actualization of deterrence through engaging in cyber attacks. Regardless of whether these major cyber powers' evolving strategic thinking on cyber deterrence will prove logically consistent or feasibly operational, their respective perspectives will certainly shape their attempts to achieve cyber deterrence. Ultimately, cyber deterrence may continue to be "what states make of it," given conditions of "cyber anarchy" and prevailing uncertainties regarding cyber conflict. Looking forward, future strategic stability in Sino-U.S. cyber interactions will require mitigation of the misperceptions and heightened risks of escalation that could be exacerbated by these divergent strategic approaches.

关键词： programmable logic arrays Cyberspace Resilience Context US Department of Defense Instruments Economics

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Towards Implementing Product Line Architecture

Towards Implementing Product Line Architecture

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IEEE/ACM International Workshop on Bringing Architectural Design Thinking Into Developers Daily Activities (BRIDGE)

作者： Yongjie Zheng Cuong Cu Department of Computer Science and Electrical Engineering University of Missouri - Kansas City Kansas City Missouri USA

ISBN: (纸本)9781509021963

A primary challenge involved in implementing product line architecture is realization of the included variation points (e.g. alternative components, optional interfaces) in source code. Existing architecture implementation techniques are focused on single system development. Software variability implementation techniques such as inheritance and overloading mainly support fine-grained variations at the programming language level. In this paper, we present a novel approach to implementing product line architecture. It combines a code generation and separation pattern with an architecture-based code annotation technique. It can support product line variability in platforms, functions, and implementation mechanisms that are at different degrees of granularity. The goal is to maintain architecture-implementation conformance and increase code reusability.

关键词： programmable logic arrays Computer architecture Software Object oriented modeling Urban areas Computer languages Software architecture

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